Assessment of population status of hinde’s babbler (turdoides hindei) in relation to its habitat in Meru national park, Ngaya forest and the adjacent agricultural landscape, Kenya

Abstract

Populations of avian species continue to decline worldwide due to the various types of habitat degradation. This is the case with Hinde’s Babbler which is listed as Vulnerable in the IUCN Red List with isolated populations confined to some parts of central and eastern Kenya. The purpose of this study was to asses and compare its current population status in MNP, Ngaya Forest Reserve and agricultural landscapes. This survey was conducted between June and December, 2015 covering dry and wet season. Data was collected at points along predetermined transects where playback of Hinde’s Babbler was used to elicit response of Hinde’s Babbler groups. A cumulative transect length of 19km was surveyed in the three landscapes where quadrats of 20 x20m were set at constant intervals. At each point of detection, total number of adults, offsprings, disturbances, threats and vegetation attributes were recorded. Mann-Whitney, Kruskal Wallis, mean, frequencies and Spearman Rank Test were used to analyze data. The results indicated a mean group size of 4.7 at Ngaya Forest Reserve, 4.6 in MNP and 3.4 at the AS during dry season. These resulted in a population estimate of 127 individuals (Ngaya), 91 individuals (MNP) and 98 individuals (AL). During wet season the mean group size in Ngaya Forest Reserve was 5.2, 3.9 in MNP and 4.0 in AS. This resulted in population estimate of 84 individuals at Ngaya Forest, 123 in MNP and 38 individuals at AS. There was no significant statistical difference between group density during dry and wet sampling season (W = 241.5, P =0.08). In terms of relationship with habitat, only shrub cover was positively correlated with mean group size of Hinde’s Babbler in both seasons (dry, rs = 0.70, P=0.01; wet, rs = 0.80, P=0.02). The other variables of tree, herbaceous and grass cover (rs = -0.57, P= 0.03; rs = -0.83, P = 0.00, rs = - 0.54, P = 0.04) were negatively correlated during the dry season while no correlation was established between mean group size with bare and with crop cover. During the wet season, only tree cover was negatively correlated with mean group size. In terms of disturbance and threats to Hinde’s Babbler, only vegetation trampling in MNP was correlated with mean group size during the wet season (rs = - 0.26, P =0.03). These results imply that continuous monitoring of these three landscape and habitat is necessary to keep track of trends in population and the impact of disturbance on the conservation of the Hinde’s Babbler. The results are crucial in underscoring the importance of protected, partially protected and agricultural landscape as well as habitat structure and condition in the conservation of threatened avifauna population.